Cleaning member, charging device, transfer device and image forming apparatus

ABSTRACT

The present invention provides a cleaning member including melamine resin foam in at least a portion that contacts an object to be cleaned. A charging device and a transfer device including the cleaning member are provided as well. An image forming apparatus including at least the cleaning member is also provided. In the image forming apparatus the cleaning member cleans at least one of a charge roll of the charging device, an image carrier, and a transfer roll of the transfer device.

This is a Reissue of U.S. Pat. No. 6,701,105, issued Mar. 2, 2004, whichissued from U.S. application Ser. No. 10/228,333, filed Aug. 27, 2002,which claims the benefit of Japanese Patent Application No. 2010-256316,filed Aug. 27, 2001. The disclosure of each of the prior applications ishereby incorporated by reference herein in its entirety.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a cleaning member, a charging device, atransfer device and an image forming apparatus used for a printer, acopying machine, or the like.

2. Description of the Related Art

In general, an image forming process in an electrophotographic imageforming apparatus using a toner as a developing agent comprises mainlythe following steps:

-   -   (1) preliminary exposure of an image carrier (photosensitive        member) (this step can be omitted when an alternating current        voltage is applied to a direct current voltage so as to be        superimposed thereon, as has been carried out recently),    -   (2) charging the image carrier surface,    -   (3) forming a latent image by exposure,    -   (4) forming a visual image using toner,    -   (5) transferring the toner image onto a transfer material        (paper, or the like),    -   (6) cleaning the image carrier surface after the transfer, and    -   (7) fixing the toner image on the transfer material by heating,        or the like.

Recently, as an important issue for electrophotographic image formingapparatuses, attention has been paid to making the life of theapparatuses longer.

This is aimed at reducing the film reduction of the image carrierdisposed in the center of the electrophotographic image formingapparatus so as to maintain good image formation for a longer time. Thisin turn is greatly effective in reducing operating cost.

It is known that the charging mechanism is greatly influenced by filmreduction of the image carrier. Types of the charging mechanism varywidely. For example, contact charging, which has been in use for about10 years, is for applying a charging bias by rotatingly a charge rollerwhich comprises an elastic member with resistance adjusted so as to besemi conductive (about 10⁵ Ωcm),in contact with the image carrier. Thecharge bias at a time when an alternating current voltage having aninter-peak voltage of at least two times as high as a discharge startingvoltage of a direct current is superimposed and applied to a directcurrent voltage. Due to the application of the alternating currentvoltage, the potential of the image carrier surface is converged to theapplied direct current voltage value, and as a result, uniform chargingof the image carrier surface can be achieved.

Moreover, since the above-described contact charging utilizes pulsedischarge in a minute space between the image carrier and the chargeroller, a generated amount of ozone, which is harmful to human bodies,can be kept to an extremely small amount compared with a corotroncharge, which was used previously, and drastic reduction in a cost ofthe charge member can be achieved. Thus, contact charging is now in themainstream of charging methods.

However, since contact charging changes the image carrier surface byutilizing pulse discharge as described above, the image carrier surfaceis always in an etched state. This results in a harmful effect in thatthe film reduction of the image carrier is further accelerated.

Therefore, in order to reduce the film reduction of the image carrier byrestraining the pulse discharge, the following novel charging mechanismshave been proposed.

(1) Direct Current (DC) Charging (a Method of Applying only a DirectCurrent Voltage to the Contact Charge Roller)

This method is for charging the image carrier surface only using directcurrent voltage. Since alternating current voltage is not applied, theamount of current flowing to the image carrier is extremely small. Thatis, the pulse discharge to the image carrier is reduced as well. As aresult, etching with regard to the image carrier (photosensitive member)is reduced, and the film reduction of the image carrier is kept to asmaller amount.

(2) Non-contact Charging (a Method of Applying an Alternating CurrentVoltage Superimposed on a Direct Current Voltage while Providing aCertain Gap between the Image Carrier and the Charge Roller)

Compared with contact charging (when applying an alternating currentvoltage superimposed on a direct current voltage), this method has anextremely small inflow of current to the image carrier. In contrast to acurrent generated by a nip of the charge roller and the image carrierand a discharge current accompanying a pulse discharge generated in agap in a range satisfying the Paschen's discharge start voltage existingon the right and left sides of the nip by the contact charge, byproviding a certain gap between the image carrier and the charge rollerthe nip current generation can be prevented and the pulse discharge isgenerated only at the shortest part of the gap between the image carrierand the discharge roller. Thus, etching with respect to the imagecarrier can be reduced so that the film reduction of the image carriercan be kept to a small amount.

However, the above-described charging mechanisms respectively have thefollowing problems.

(1) Direct Current (DC) Charging

The amount of discharge current in DC charging is determined by aresistance value of the contact charge roller, so that the pulsedischarge state depends largely on the properties of a surface of thecontact charge roller. Therefore, in order to uniformly charge only byapplying a direct current voltage on the image carrier surface, comparedwith the case of applying an alternating current voltage superimposed ondirect current voltage, a further even electric resistance and surfacesmoothness are required. Therefore, in order to improve the electricresistance evenness and the surface smoothness, cost increase cannot beavoided.

Moreover, according to the DC charging, contamination (transfer toner,paper dusts, or the like) can easily adhere to the charge rollersurface. Since the electric resistance and the surface condition arevaried by the adhered contamination, the uniform charging can easily beinhibited. This is considered that the contamination adhered on thecharge roller can hardly be eliminated due to absence of the oscillatingelectrolysis because the alternating current voltage is not applied.

Therefore, in order to maintain a exellent image over a long time whilereducing the film reduction of the image carrier according to the DCcharging, a cleaning mechanism for the charge roller or a mechanism forcompletely preventing adhesion of contamination on the charge roller isindispensable.

With respect to the above-described problems, a method of forming thesurface layer of the charge roller with a high mold releasing propertymaterial, a method of applying an inverse bias which is polarityopposite to the charge polarity every certain period of time forinverting the polarity of the residual toner so as to be moved onto theimage carrier, or the like have been attempted. However, the moldreleasing property of the surface is lowered as time passes by as wellas the effect of the inverse bias is lowered, so that a high imagequality cannot be provided over a long time in the present situation.

(2) Non-contact Charging

According to the non-contact charging, since a certain gap is providedbetween the image carrier and the charge roller, the applied biasnecessary for charging should be increased. This is apparent from theapproximate expression of the Paschen's discharge start voltage:VTH=312+6.2×Z (Z is gap amount (μm)).

The increase of the applied bias brings about increase of the ozonegenerating amount, so that the amount of the discharge product (NOx, orthe like) adhered on the image carrier surface is increased.

Moreover, in the case of applying an alternating current voltagesuperimposed on a direct current voltage in the non-contact charging,since the alternating current applied bias is naturally increased aswell, the potential difference between the charging member surface andthe image carrier surface is enlarged. Thereby, the charging member caneasily attract the transfer residual toner, the paper dusts, or the likeon the image carrier. As a result, the contamination accumulation amounton the charging member tends to be increased.

SUMMARY OF THE INVENTION

In view of the above-described situation, a subject of the presentinvention is to provide a cleaning member, a charging device, a transferdevice and an image forming apparatus, capable of reducing wear of anobject to be cleaned such as an image carrier to an extremely smallextent so as to maintain the performance of a charging member in a goodstate over a long time.

A cleaning member according to a first aspect of the invention comprisesmelamine resin foam in at least a portion thereof that contacts anobject to be cleaned.

Further, a charging device according to another aspect of the inventioncomprises a cleaning member for cleaning an object, the cleaning membercomprising melamine resin foam in at least a portion thereof thatcontacts the object to be cleaned; and a charge roller.

Furthermore, a transfer device according to still another aspect of theinvention comprises a cleaning member for cleaning an object, thecleaning member comprising melamine resin foam in at least a portionthereof that contacts the object to be cleaned; and a transfer roller.

Moreover, an image forming apparatus according to yet another aspect ofthe invention comprises at least the cleaning member according to thefirst aspect, wherein the cleaning member cleans at least one of acharge roll of a charging device, an image carrier, and a transfer rollof a transfer device.

The image forming process of the image forming apparatus can be forexample, an electrophotography process, an electrostatic recordingprocess, a magnetic recording process, or the like.

Moreover, the image carrier in the invention is a photosensitive member,an intermediate transfer member, or the like, and the shape thereof canbe cylindrical, belt-like, or the like and it is not particularlylimited.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is diagram for explaining the state with a cleaning member of thepresent invention contacted with an object to be cleaned.

FIG. 2 is a schematic configuration view showing an embodiment of animage forming apparatus comprising the cleaning member of the invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

A cleaning member, a charging device, a transfer device and an imageforming apparatus of the invention will now be explained.

Cleaning Member

A cleaning member according to the invention comprises melamine resinfoam in at least a portion thereof that contacts an object to becleaned.

The melamine resin foam in general can be prepared by a method ofcompounding catalyst, emulsifying agent, or the like to a main rawmaterial such as melamine, formaldehyde, or the like, and after addingand mixing foaming agent therein, directing an electron beam thereon.

Moreover, it is preferable that the melamine resin foam has athree-dimensional mesh-like structure. The “three-dimensional mesh-likestructure” denotes a structure with a sub micron order fiber-likemelamine resin coupled three-dimensionally in a state finely entangledwith each other so as to form minute cells.

According to the melamine resin foam having the three-dimensionalmesh-like structure, the sub micron order fiber-like melamine resinenters into the minute ruggedness on the image carrier or the chargingmember so as to scrape out dust such as residual toner and paper dustsso that the surface of the image carrier, the charging member, or thelike can be maintained in a state without contamination.

Moreover, since the sub micron order fiber-like melamine resin canprovide cleaning performance without being strongly pressed against theimage carrier or the charging member, the melamine resin does not damagethe surface of the image carrier of the charging member or does not fixcontamination on the surface of the image carrier or the chargingmember.

Furthermore, according to the conventional cleaning sponge, since onlyclosed or open cells are provided, the cells can be easily clogged bydust. In contrast, by using the cleaning member having thethree-dimensional mesh-like structure, since collected dust does notremain in one cell and dust will not become clogged therein, theperformance of the cleaning member can be maintained over a long time.

The three-dimensional mesh-like structure of the melamine resin foamhaving the three-dimensional mesh-like structure can be formed asfollows. Sufficiently kneading a melamine resin and a resin whichdissolves by a specific solvent, heat-curing the same, and by soakingthe same in the specific solvent, a three-dimensional mesh-likestructure with only the melamine resin part remaining can be provided.

Moreover, as the melamine resin foam, a commercially available productmay be used as well. For example, BASOTECT produced by BASF Ltd., can beused. Since BASOTECT has a heat-cured three-dimensional mesh-likestructure, the above-described effects can be provided.

It is preferable that the cleaning member of the invention is used forcleaning at least one of objects to be cleaned, such as an imagecarrier, a charging member and a transfer member. The charging member tobe cleaned denotes mainly a charge roll, and the transfer member denotesmainly a transfer roll.

The shape of the cleaning member according to the invention is notparticularly limited, and various shapes such as a brush shape, a padshape and a roller shape can be used. Moreover, the whole cleaningmember may be constructed of melamine resin foam. The cleaning membermay, however, be constructed so that only a portion of the cleaningmember which abuts the image carrier or the charging member comprisesmelamine resin foam.

The cleaning member according to the invention may be either insulativeor conductive.

If the cleaning member is conductive, the cleaning member may serve alsoas a charging member for charging the image carrier. Moreover, if thecleaning member is conductive, a cleaning bias may be applied thereon.Furthermore, here “conductive” means semi conductive as well.

The method for imparting conductivity to the cleaning member is notlimited, and conventional method such as including a conductive materialin the cleaning member blowing conductive particles onto the cleaningmember, or the like can be used. However, it is preferable to useimpregnation which is a method of impregnating a cleaning member with aconductive varnish with electric resistance adjusted to 10³ to 10¹⁰ Ω(preferably 10⁴ to 10⁸ Ω). According to the impregnating method, acleaning member with an extremely stable electric resistance can beprovided at extremely low cost.

Examples of the conductive varnish, include those prepared by dispersingcarbon in urethane, silicon, styrene, or the like, and dissolving thesame in a solvent (such as ethyl acetate, toluene and methyl ethylketone), or the like.

It is preferable that the cleaning member of the invention is disposedso as to approach and/or separate freely from an object to be cleanedsuch as an image carrier, a charging member and a transfer member.

In the case a cleaning operation is not required (in a case such as theimage forming apparatus is stopped for a long time), or in the case thecleaning is used as a cleaning member for an intermediate transfermember of a four cycle color image forming apparatus (an image formingapparatus of repeating a step of transferring a toner image from aphotosensitive member to an intermediate transfer member for each offour colors of Y, M, C, K), the cleaning member is need to be disposedaway from the image carrier, the charging member, or the like.

Moreover, it is preferable that the cleaning member of the invention isdisposed so as to reciprocally move in the axis direction of the objectto be cleaned. Specifically, as shown in FIG. 1, it is preferable that amelamine resin foam portion 1a of the cleaning member 1 is disposed soas to abut the surface of the roll-like object to be cleaned 2 in astate being movable to freely approach/separate therefrom, and beingmovable reciprocally in the axis direction of the object to be cleaned2. According to the configuration, the surface of the object to becleaned 2 can be cleaned evenly.

Charging Device, Transfer Device

The charging device of the invention includes the above-describedcleaning member. Specifically, the charging device is preferable to beconstructed so that the cleaning member is provided so as to freelyapproach/separate from the charge roller surface.

The transfer device of the invention includes the above-describedcleaning member. Specifically, the transfer device is preferable to beconstructed so that the cleaning member is provided so as to freelyapproach/separate from the transfer roller surface.

Image Forming Apparatus

A schematic configuration of the image forming apparatus including thecleaning member of the invention is shown in FIG. 2. The image formingapparatus shown in FIG. 2 includes an image carrier 10 as anelectrophotography photosensitive member, a charge roll 12 as a contactcharging type charging device, a laser exposing optical system 14, adeveloper 16 using a developing material (toner), a transfer roll 18 asa transfer device and fixing rolls 22. The cleaning member 11 isprovided so as to freely approach/separate from the surface of the imagecarrier 10, the transfer roll 18 and the charge roll 12. Further, if thecleaning member is conductive, a cleaning bias 15 may be appliedthereon.

The position of providing the cleaning member 11 is not limited to theabove-described embodiment, and is provided for cleaning at least one ofthe charge roll 12, the image carrier 10 and the transfer roll 18.

The image forming mechanism will be explained with reference to theimage forming apparatus shown in FIG. 2. First, the surface of the imagecarrier 10 is uniformly charged by the charge roll 12. Light isirradiated to non-image portions thereof by the optical laser-exposuresystem 14 to eliminate the electric charge at the portions to whichlight is irradiated so as to form an electrostatic latent image with theelectric charge remaining in the image portions. In the developer 16using a toner as a developing agent, the toner which is charged to thereversed polarity of the electrostatic latent image is adhered to theelectrostatic latent image so as to form a visible image, i.e., a lonerimage (developing step). Next, a toner-receiving member 17 is insertedbetween the photosensitive member 10 having the toner image formedthereon and the transfer roll 18, and the toner image is supported onthe toner-receiving member 17 so as to transfer the toner image onto thetoner-receiving member 17 (transfer step). The transferred toner imageis moved to two fixing rolls 22 contacting each other, and is passedthrough a nip portion of the two fixing rolls 22 for fixation by heatand/or pressure so that an image is formed (fixing step).

The toner on the surface of the image carrier 10 which did not betransferred (residual toner) is eliminated by the cleaning member 11.Moreover, the residual toner, or the like adhered on the charge rollsurface is eliminated by the cleaning member 111 as well. By repeatingthe series of the process, the process from charging the toner to theprocess to eliminate the residual toner, images can be formedsuccessively.

Here, as to the shape of the cleaning member 11, known shapes such as aroll shape, a pad shape and a brush shape can be adopted.

In the image forming apparatus having the cleaning member of theinvention, it is preferable to use a spherical toner capable of usingvarious kinds of developing agents. It is more preferable to use aspherical toner produced by the polymerization method.

Since the spherical toner produced by the polymerization method isspherical (preferable sphericity (shape coefficient SF-1): 100 to 150)and the particle diameter thereof is extremely homogeneous, it providesa high transfer efficiency to a transfer material (paper) so as to forma sharp image.

The image carrier 10 preferably includes a surface layer 9 (outermostlayer) having the charge transportation property, produced from asiloxane based resin having a cross-linking structure.

Since the surface layer of the image carrier is a film produced from asiloxane based resin having a cross-linking structure to be hardlyabraded, since the surface film reduction can be restrained to anextremely small extent, a longer life can be achieved so that therunning cost can be reduced as well.

EXAMPLES

The present invention will be explained with reference to the followingexamples. However, the invention is not limited thereto.

Example 1

A layer comprising a melamine resin foam (BASOTECT, produced by BASFLtd.) was adhered to an outer circumferential surface of a 4 mm diametermetal (SUS) core metal using a conductive adhesive (SHINTRON D-4256,produced by Shinto Paint Co., Ltd.). A thickness of the layer wasadjusted to 2 mm via rotational polishing so as to produce cleaningmembers with an 8 mm outer diameter.

An average cell diameter of the produced layer comprising the melamineresin foam formed on the outer circumferential surface of the cleaningmember was 3 μm.

As shown in FIG. 2, the produced cleaning members were respectivelymounted at a cleaning position for an image carrier and a cleaningposition for a charging member in a black and white image formingapparatus so as to respectively bite 0.3 mm into the image carrier andthe charging member.

At the time, as the image carrier, a photosensitive material coated by asiloxane based resin film having a cross-linking structure by a 3 μmthickness as the outermost layer was used. As the toner, an acrylicbased polymerized toner (volume average particle diameter 5.5 μm) wasused.

Moreover, as the charging member, a charge roller with a two-layerconstruction having an EPDM (Ethylene Propylen Dien Monomer) foam layer(thickness: 3 mm) and a tube covering layer (thickness: 1 mm), whichincluded a styrene based elastomer, formed successively on an outercircumferential surface of a 6 mm diameter metal core was used.

Using the above-described image forming apparatus, a 50,000 sheet imageoutputting test was executed under the following (1) to (3)environments. The applied bias was a direct current voltage −1,400 V.

Environment

-   -   (1) High temperature/high humidity environment (temperature: 28°        C., humidity: 85% Rh)    -   (2) Low temperature/low humidity environment (temperature: 10°        C., humidity: 15% Rh)    -   (3) Standard environment (temperature: 22° C., humidity: 55% Rh)        According to the result of the test, it was found that any        problem was not found either in images in the initial stage or        the 50,000th image in any of the (1) to (3) environments, and        abnormalities such as flaws or pin holes were not observed at        all in the image carrier or the charging member.

Moreover, after the test, the abrasion amount of the CT layer (chargetransportation layer) of the image carrier was 0.2 μm in the lowtemperature/low humidity environment (temperature: 10° C., humidity: 15%Rh). Contamination was scarcely found on the charge roller surface, orsignificant change such as flaws and stripes were not observed as well.

Example 2

To 100 parts by mass of phenol resin, 5 parts by mass of glass fiber, 3parts by mass of talc, 2 parts by mass of calcium oxide, 5 parts by massof conductive carbon black, 15 parts by mass of conductive titaniumoxide, 3 parts by mass of conductive tin oxide, 3 parts by mass ofdispersion auxiliary agent (zinc stearate), and 1 part by mass ofsurface modifier (silicon based waxes) were added. After dry blending,the material was extrusion molded into a pipe-like shape by using atwo-ax extruder so as to produce a compact.

A metal shaft with a conductive adhesive apllied thereon waspress-fitted into the produced compact pipe. Thereafter, a polishingoperation was performed using a centerless polishing device so as tomake a 14 mm pipe outer diameter for producing a charge roller.

The hardness of the produced charge roller was 95 degrees in Asker C.The electric resistance was 1×10⁶ Ωcm in all of the testing environment,the high temperature/high humidity environment (temperature: 28° C.,humidity: 85% Rh), the low temperature/low humidity environment(temperature: 10° C., humidity: 15% Rh), and the standard environment(temperature: 22° C., humidity: 55% Rh). The surface smoothness thereofwas 0.8 μm in Rz.

Moreover, the outer diameter deflection measured at three points in thelongitudinal direction was 10 μm or less, and the straightness of asingle resistance layer was 10 μm or less, and thus a charge roller withan extremely high accuracy was provided.

Spacer members (collars) 30 μm made of POM (polyacetal) were mounted onboth of the ends in the longitudinal direction of the produced chargeroller, and the charge roller it was mounted in the image formingapparatus shown in FIG. 2 for producing a non-contact charge roller witha gap with respect to the image carrier set at 30 μm.

In the same process as in Example 1 except that the charge roller was anon-contact charge roller, a 50,000 sheet image outputting test wasperformed with the cleaning member provided.

As to the applied bias here, 2,400 Vpp alternating current voltage wasapplied and superimposed on −700 V direct current voltage by 1,500 Hzfrequency.

Moreover, as the image carrier at the time, an ordinary OPC (organicphoto-conductor) photosensitive material was used. As the toner, anacrylic based polymerized toner (volume average particle diameter: 5.5μm) was used.

As a result, it was found that any problem was not found either inimages in the initial stage or the 50,000th image in any of the testingenvironment, the high temperature/high humidity environment(temperature: 28° C., humidity: 85% Rh), the low temperature/lowhumidity environment (temperature: 10° C., humidity: 15% Rh), and thestandard environment (temperature: 22° C., humidity: 55% Rh), andabnormalities such as flaws and pin holes were not observed at all inthe image carrier or the charging member.

The abrasion amount of the CT layer of the image carrier was 0.2 μm inthe low temperature/low humidity environment (temperature: 10° C.,humidity: 15% Rh).

Moreover, contamination was scarcely found on the charge roller surface,or significant change such as flaws and stripes were not observed aswell.

Example 3

In the same manner as in Example 1, a layer (thickness: 2 mm) comprisingmelamine resin foam was formed on an outer circumferential surface of a4 mm diameter metal (SUS) core metal. Then, after being soaked(impregnated) in a conductive varnish (EMRALON JLY601, produced byAcheson Japan Limited) having electric resistance adjusted to 10⁵ Ω forproviding semi conductivity, vibration was applied by ultrasonic wavesfor sufficiently permeating the conductive varnish to the deepest partof the melamine resin foam. The solution was dried at 80° C. for 10minutes so as to produce a cleaning member with an 8 mm outer diameter.

An average cell diameter of the produced cleaning member was 3 μm, andthe electric resistance was 5×10⁸ Ω.

In the same manner as in Example 1 except that the above-describedcleaning member was used, a 100,000 sheet image outputting test wasperformed in each environment.

As the image carrier, one coated to a 3 μm thickness at an outermostlayer with a siloxane based resin film having a cross-linked structurewas used. As the toner, an acrylic based polymerized toner (volumeaverage particle diameter 5.5 μm) was used.

Moreover, the bias applied to the image carrier was direct currentvoltage −1,400 V, and a cleaning cycle was provided in which an inversebias and a normal bias were alternately applied for 2 seconds per 500sheets of image formation.

As a result, it was found that any problem was not found either inimages in the initial stage or the 100,000th image in any of the testingenvironment, the high temperature/high humidity environment(temperature: 28° C., humidity: 85% Rh), the low temperature/lowhumidity environment (temperature: 10° C., humidity: 15% Rh), and thestandard environment (temperature: 22° C., humidity: 55% Rh).

The abrasion amount of the CT layer of the image carrier at the time was1.2 μm in the low temperature/low humidity environment (temperature: 10°C., humidity: 15% Rh).

Moreover, contamination was scarcely found on the image carrier surfaceor the charge roller surface, or significant change such as flaws andstripes were not observed as well.

Comparative Example 1

In the same manner as in Example 1 except that a urethane sponge (celldiameter: 50 μm) was used as the cleaning member, a 50,000 sheet imageoutputting test was performed in each environment (above-described (1)to (3)).

As a result, image deficiency such as streaked (striped) uneveness wasobserved on the images from about 5,000th sheets in the lowtemperature/low humidity environment (temperature 10° C., humidity 15%Rh).

At the same time, from the observation of the surface of the imagecarrier and the charge roller, deep stripes and toner adhesion wereobserved at the position corresponding to the stripes on the image.

This phenomenon further deteriorated according to increase of the imageformation number, and the stripe-like pattern was observed on the entiresurface of the 50,000th image.

Furthermore, from the observation of the cleaning member, clogged tonerand paper dusts were found in most of the cells which were observed.

Comparative Example 2

In the same manner as in Example 3 except that an EPDM sponge(electrical resistance: 4×10⁸ Ω, cell diameter: 50 μm)having semiconductivity was used as the cleaning member, a 50,000 sheet imageoutputting test was performed in each environment (above-described (1)to (3)).

As a result, image deficiency such as streaked (striped) uneveness wasobserved on the images from about 10,000th sheets in the lowtemperature/low humidity environment (temperature 10° C., humidity 15%Rh).

At the same time, from the observation of the surface of the imagecarrier and the charge roller, deep stripes and toner adhesion wereobserved at the position corresponding to the stripes on the image.

This phenomenon further deteriorated according to increase of the imageformation number, and the stripe-like pattern was observed on the entiresurface of the 50,000th image.

What is claimed is:
 1. A cleaning member for cleaning an object that isat least one of an image carrier, a charging member and a transfermember, the cleaning member comprising: a conductive melamine resin foamin at least a portion thereof that contacts the object to be cleaned,wherein the conductive melamine resin foam has a three-dimensional meshstructure, and the cleaning member is formed in a roller shape and is aconductive member.
 2. The cleaning member according to claim 1, whereinthe cleaning member is formed in a pad shape or a roller shape.
 3. Thecleaning member according to claim 2, wherein the cleaning member is aninsulative material.
 4. The cleaning member according to claim 2 1,wherein the cleaning member is a conductive member and can be used as acharging member.
 5. The cleaning member according to claim 4, whereinthe conductive property of the cleaning member is provided byimpregnating the cleaning member with a conductive varnish.
 6. Thecleaning member according to claim 5, wherein the cleaning member isdisposed to freely approach and/or separate from the object to becleaned.
 7. The cleaning member transfer device according to claim 6 13,wherein the cleaning member is disposed to move reciprocally in an axisdirection of the object to be cleaned transfer roller.
 8. The cleaningmember according to claim 7, wherein a cleaning bias is applied to thecleaning member.
 9. An image forming apparatus comprising the cleaningmember according to claim 1, wherein a spherical toner is used as adeveloping agent.
 10. The image forming apparatus according to claim 9,wherein a surface layer of the image carrier has a charge transportationproperty and comprises a siloxane based resin having a cross-linkingstructure.
 11. A charging device comprising: a charge roller; and acleaning member for cleaning an object the charge roller, the cleaningmember comprising a conductive melamine resin foam in at least a portionthereof that contacts the object to be cleaned charge roller, whereinthe conductive melamine resin foam has a three-dimensional meshstructure; and a charge roller, and the cleaning member is formed in aroller shape and is a conductive member.
 12. The charging deviceaccording to claim 11, wherein the cleaning member is disposed to freelyapproach and/or separate from a surface of the charge roller.
 13. Atransfer device comprising: a transfer roller; and a cleaning member forcleaning an object the transfer roller, the cleaning member comprising aconductive melamine resin foam in at least a portion thereof thatcontacts the object to be cleaned transfer roller, wherein theconductive melamine resin foam has a three-dimensional mesh structure;and a transfer roller, and the cleaning member is formed in a rollershape and is a conductive member.
 14. The transfer device according toclaim 13, wherein the cleaning member is disposed to freely approachand/or separate from a surface of the transfer roller.
 15. The cleaningmember according to claim 1, wherein the cleaning member has an electricresistance of from 10³ to 10¹⁰ Ω.
 16. The cleaning member according toclaim 1, comprising: a core; and an outer circumferential sheetlaminated on an outer circumferential surface of the core, the outercircumferential sheet comprising the conductive melamine resin foam as aportion thereof that contacts the object to be cleaned.
 17. The cleaningmember according to claim 1, wherein the conductive melamine resin foamcomprises melamine resin foam impregnated with a conductive varnish. 18.The transfer device according to claim 13, wherein the conductivemelamine resin foam comprises melamine resin foam impregnated with aconductive varnish.
 19. The charging device according to claim 11,wherein the cleaning member comprises: a core; and an outercircumferential sheet laminated on an outer circumferential surface ofthe core, the outer circumferential sheet comprising the conductivemelamine resin foam as a portion thereof that contacts the chargeroller.
 20. The charging device according to claim 11, wherein theconductive melamine resin foam comprises melamine resin foam impregnatedwith a conductive varnish.